Mecanismo de ação auxínica

Castro, Paulo R.C.

doi:10.1590/S0071-12761979000100034

Resumos

As principais hipóteses envolvendo o mecanismo de ação das auxinas são consideradas com a finalidade de apontar os processos mais prováveis de acordo com os conhecimentos atuais. Ácidos nucléicos e proteínas devem estar relacionados com modificações na parede celular através da secreção de íons hidrogênio e estimulação na atividade enzimática capaz de promover afrouxamento e elongação da parede celular. Um esquema indicando os processos de ação auxínica capazes de alterações na parede celular, é apresentado.

Present evidence suggests the following picture for cell wall extension: there is the possibility that auxin acts to induce synthesis of nucleic acids and proteins which presumably are envolved in cell enlargement through enzyme activation and cell wall components synthesis. Rapid responses to auxin may be through the auxin activation of a proton pump on the plasmalemma. The resultant lowering of the pH in the wall enhances the activity of wall-loosening enzymes there promoting cell wall enlargement. A schematic representation of the mechanism concerning the action of auxin in elongation growth is presented.

Paulo R.C. Castro

Departamento de Botânica, E.S.A. "Luiz de Queiroz", USP

RESUMO

As principais hipóteses envolvendo o mecanismo de ação das auxinas são consideradas com a finalidade de apontar os processos mais prováveis de acordo com os conhecimentos atuais. Ácidos nucléicos e proteínas devem estar relacionados com modificações na parede celular através da secreção de íons hidrogênio e estimulação na atividade enzimática capaz de promover afrouxamento e elongação da parede celular. Um esquema indicando os processos de ação auxínica capazes de alterações na parede celular, é apresentado.

SUMMARY

Present evidence suggests the following picture for cell wall extension: there is the possibility that auxin acts to induce synthesis of nucleic acids and proteins which presumably are envolved in cell enlargement through enzyme activation and cell wall components synthesis. Rapid responses to auxin may be through the auxin activation of a proton pump on the plasmalemma. The resultant lowering of the pH in the wall enhances the activity of wall-loosening enzymes there promoting cell wall enlargement. A schematic representation of the mechanism concerning the action of auxin in elongation growth is presented.

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LITERATURA CITADA

Entregue para publicação em 14.12.1979.

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